Conventionally, a surface of a semiconductor wafer is polished using a chemical mechanical polishing (CMP) apparatus by independently rotating a turntable and a top ring of the CMP apparatus with the semiconductor wafer held therebetween.
A variety of chemical solutions for polishing are fed from the turntable or the top ring to the semiconductor wafer being polished. Also, air and water used for vacuum suction of the semiconductor wafer, air spouting, or water spouting, for example, are fed from the turntable or the top ring.
The turntable and the top ring are rotatably supported by a fixed main body of the CMP apparatus. A rotary joint is disposed between the main body and the turntable or the top ring in such a manner that a variety of chemical solutions, air, and water, for example, can flow through the rotary joint without leakage.
A generally known rotary joint structure includes a cylindrical shaft and a cylindrical housing surrounding the shaft. The shaft and the housing are arranged so as to be capable of relative rotation in such a manner that a variety of chemical solutions, for example, can flow from the housing to the shaft, or from the shaft to the housing, without leakage (for example, see Patent Document 1).    Patent Document 1: U.S. Pat. No. 5,713,609